Some metal painting advice

[dunstan]

I have two questions I'm looking for advice on.

[1] I have a bunch of small metal boxes, like the one below, that I'd like to repaint. Some of them I've completely stripped back to the bare metal, but some have tricky nooks and crannies that are hard to get to.

I'm wondering if anyone can give me a simple guide to repainting them.



I've painted a bunch of things for my car using a base coat of Dupli-Color Engine Enamel with Ceramic – Grey Engine Primer and then one of the the colored paints from the same series. However, I'm now wondering if I'm missing out on a trick, because I see people talking about etching primers and so on, but I'm not sure what they are and if they're necessary for what I want. I also wonder if I really need to remove every single speck of paint and rust from everywhere, or if these base coats I see people using take care of sealing light surface rust too, and preventing later eruptions.

[2] I recently repainted my drill press using the same base coat of Dupli-Color Engine Enamel with Ceramic – Grey Engine Primer and then one of the the colored paints from the same series. I used two light and one heavy coats of primer, and then two light and two heavy coats of color. I thought that would be good, but yesterday I accidentally banged two of the parts together and the paint chipped. Is paint normally that fragile? Or did I not put enough layers on?

Thanks for any advice you can offer.

 

[astroracer]

Chipping paint means there is no adhesion, either to the base metal or between coats of paint. Getting everything clean and scuffed is key to a good paint job.
For what you are doing I would recommend removing all of the rust and sanding with 180 grit paper before priming. Wash and dry the part in hot water with some TSP added. The TSP is a grease remover and will get the oil and grease off the part prior to painting. I would also wipe the part down with some Prep-Sol (another pre-paint degreaser) before spraying any paint.
The primer will need to be scuffed also and I would recommend using a medium ScotchBrite pad to get into all of the crannies. The ScotchBrite is much more versatile at doing this then a stiff piece of paper. After scuffing de-grease with the Prep-Sol again, before spraying any more paint. Going through these steps will help in making for a nice, long lasting paint job on your boxes.
Mark

 

[Jere]

I would wire wheel it all the way clean , wipe it off then self etching then whatever your next coat is . Just don't let it sit a few days or rust could start

There is always the dip with the car battery charger deal too, not sure how well that will do on the well bonded paint.

 

[Shopmaster]

A bead blast cabinet would be perfect for these boxes. If you don't have one find someone local and pay them. It will be worth the money.

 

[gorilla]

A bare steel surface has a coating of iron oxide on it. Paint won't stick to iron oxide. Before painting good practice is to convert the surface to iron phosphate. This is done with products that contain phosphoric acid. One common one is metal prep, your local auto body store should have one of these products in stock. Self etching primers are suppose to do the same thing. The only rattle can primer of that sort that works well in my opinion is made by SEM and costs about $20.00 per can.

 

[Zeke]

On the DP, you may have put too much primer and paint on. Usually thick primer is for sanding to a smooth finish. Otherwise, less is more. Ample drying times between coats is essential.

 

[Kevin54]

I would have the boxes either bead blasted, or as small as they are, you could actually sand blast them if you don't get too aggressive with the blasting. Don't hold the blast gun too close and you should be fine. Add a coat of primer, sand lightly with some 600 grit, then paint the color of your choice.

 

[dunstan]

Thanks everyone. I just spent some time on the phone with Dupli-color and I think I probably did enough in terms of prep and de-greasing for the drill press – I didn't scuff the primer, but otherwise was quite obsessive with cleanliness and cure times. I'll put the chips down to clumsiness on my part, rather than weak paint. Additionally I'll touch up the chipped areas with a squirt of color, let it cure for a week, clean with acetone, and then stick a layer of clear coat on top to give it some more protection.

As for the boxes, I've cleaned a few of them to shining brightness with wire wool, so I'll rough them up a little with sandpaper, degrease them with hot soapy water and acetone, prime them, scuff and degrease again, then paint them. The ones with the nooks and crannies I'll just spend some extra time on. I've spent so much on sand blasting recently that I'd like to save some money if I can, but I appreciate the suggestion.

The call with Dupli-color certainly made me feel a bit better. I barely slept last night worrying I'd ballsed up a month of paint work, but I think I'll be okay.

Oh, astroracer, where do you buy prep-sol? It seems to be an oft recommended product yet I can't find it for sale any where. What's your source? I'm in California.

And since everyone likes pictures, here's the dp getting painted:


Thanks again.

-- Dunstan

p.s. Despite searching the forums last night and not turning up anything I've since discovered lots of threads like this one, so I appreciate people repeating what they've probably said elsewhere.

 

[astroracer]

Prep-Sol is Duponts wax and grease remover. PPG's is Pre-Cleano. Any automotive paint store will carry those or a generic. I use B-4 on small projects, it works well.
Mark

 

[Jere]

Nice PVC spray stand!

Sent from my Nexus 7 using Tapatalk

 

[kazlx]

Sounds like you need your own blast cabinet

 

[dunstan]

Prep-Sol is Duponts wax and grease remover. PPG's is Pre-Cleano. Any automotive paint store will carry those or a generic. I use B-4 on small projects, it works well.
Mark

Great, thank you.

Nice PVC spray stand!

Thanks! I built it specifically for this project because I knew I'd have a bunch of parts to do. I'm also painting a small lathe at the same time, so it seemed a good excuse to have a proper place for making a mess.

Sounds like you need your own blast cabinet

I've thought about it a bunch of times, but not delved into it yet. I'd certainly like to get one in the near future.

 

[Kevin54]

Great, thank you.




Thanks! I built it specifically for this project because I knew I'd have a bunch of parts to do. I'm also painting a small lathe at the same time, so it seemed a good excuse to have a proper place for making a mess.




I've thought about it a bunch of times, but not delved into it yet. I'd certainly like to get one in the near future.

I had some plans sent to me for a DIY Blast cabinet, and made out of plywood. I think I have the plans on the house computer. If you are interested, I can e-mail you the plans.

Kevin

 

[racingtadpole]

The boxes, blast them using a less aggressive media than slag or steel shot, glass bead as Kevin suggested or Walnut shell.

The engine enamel you used on the drill press isn't entirely suitable for stuff that doesn't get hot, I found this out the hard way. The engine enamel needs heat to help it cure. You'll find that no matter how good your prep it will bruise easily until its cured properly with heat.

Prep-sol should be available from any paint, crash or sign writing supplier

 

[dunstan]

I had some plans sent to me for a DIY Blast cabinet, and made out of plywood. I think I have the plans on the house computer. If you are interested, I can e-mail you the plans.

Thanks Kevin. I see plenty of affordable used ones on CL here, it's more the act of owning yet another "thing" that's holding me back. But I appreciate the offer.

 

[dunstan]

The engine enamel you used on the drill press isn't entirely suitable for stuff that doesn't get hot, I found this out the hard way. The engine enamel needs heat to help it cure. You'll find that no matter how good your prep it will bruise easily until its cured properly with heat.

Huh. I called Dupli-Color and they said that paint was a good, tough choice for the drill press and boxes. Maybe I'll call them back and get a second opinion. Thanks.

 

[retrobuilder]

My experience is engine paint when used on say a vise and painted in warm weather is very prone to chipping and actually gets quite hard and brittle. I now only use conventional Duplicolor enamel or SEM for aerosol paints. Rustoleum has an aerosol I finally like for "metallic" and a reasonable dry time and not too soft. Painting is 75% prep. oil free and use of a proper primer for top coats and application of medium to wet top coats. Avoid rainy weather and humid days- Paint ***** in moisture and blushes.

 

[dunstan]

Another quick update to say I called Dupli-Color this morning (twice, to make doubly sure), and both reps told me that the "Dupli-Color Engine Enamel with Ceramic" paint doesn't need to be heat cured; it's produced to cure at room temperature (which will take at least 7 days in ideal conditions).

One of the guys mentioned that engine enamel from their sister company, VHT, does need to be heat cured, but that the Dupli-Color product doesn't.

I know people have varied experiences of the product in real life, but I thought I'd report back on the official word.

I am mightily relieved.

 

[bsaint]

I know you already painted it, but I wouldve recommend NOT using Rustoleum primer. Takes FOREVER to dry.

 

[dunstan]

I know you already painted it, but I wouldve recommend NOT using Rustoleum primer. Takes FOREVER to dry.

Thanks for the tip. I've by only been using Dupli-Color products (though I have no experience to compare them against anything else).

 

[Richard D]

I know you already painted it, but I wouldve recommend NOT using Rustoleum primer. Takes FOREVER to dry.

Maybe so, but I don't seem to have a problem down here on the humid Gulf of Mexico. I really like the rusty metal primer, as well as the oil based enamel. I get it a Lowes, about $10-$15 a quart. Lasts a Hell of a lot longer than a spray can. Works great on projects I build out of steel. I use a brush, but would probably spray well if you thinned it.

 

[bsaint]

I've shot Rustoleum and sprayed it from a can and both times I am looking at a day for it to dry enough for shoot color.

Ive only shot Duplicolor once and I wasn't a huge fan of it. But if you can make it work - thats great!

I normally shoot Dupont products because its the best thats it locally available for me. My 2k primers are done in 15 minutes. Bases are done pretty fast also and clears I can do 3 coats in 45 minutes as long as my shop temperature is right.

 

[Richard D]

Funny, I built some pipe stands, finished them up today. I started painting, then read the directions. Said to use over 50*. It happened to be 36*. I quit painting and set them aside for tomorrow. Touched them couple hours later, it was dry. Wish I'd gone ahead and finished priming them, I could have painted tomorrow. I guess results vary.

 

[Richard D]

I painted Rustoleum late this afternoon, I was in a rush and really slopped it on thick, it's dry now. Maybe I got lucky.

 

[bsaint]

Maybe I don't know. Every can of Rustoleum Primer I buy takes hours to dry.

Maybe its just the line that grainger carries.

http://www.grainger.com/product/RUS...Rustoleum+primer|primer?sst=subset&s_pp=false

I don't know about their colors. I wouldn't buy their colors.